Probability

Practice 5 items →

Probability is a number in [0, 1]. A tree multiplies along a branch and adds across complete branches. Students compute P(E) and P(not E), list outcomes in tables and trees, and handle two-stage events with and without replacement.

Specification · for a parent or teacher

Part no.: probability-trees
Course: Advanced Math 7 · Unit 16
Realm: Applied
Difficulty: 3 of 4 — Grade 6–7 core. Multi-step, first symbolic work.
Qty: 5 items

Part no. is the node's id; the realm is the kind of math; qty is how many practice items it carries.

Students can

$P(E)=\frac{\text{favorable}}{\text{possible}}$ ; $P(E')=1-P(E)$ ; list, table, tree; single vs combined events; experimental vs theoretical; law of large numbers as a tendency, not a promise.

Ready when

two-stage tree (bag of 3 red, 2 blue, no replacement) for $P(\text{same color})$ .

Formulas

Probability

P(E) = \frac{\text{favorable}}{\text{possible}}

Complement

P(E') = 1 - P(E)

Watch for

$P(\text{H then T})=\frac12$ for two coins; adding along a branch.

Before · requires

Fractions: division and multi-step storiesfraction-operations-6 · Math 6
Ratiosratios-grade6 · Math 6

After · used by

— none

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